KR20120091175A - Electronic, especially optical or optoelectronic component, and method for the production thereof - Google Patents

Abstract

The present invention relates to an electronic, in particular an optical or optoelectronic device, which device has a component comprising a thermoplastic material, said thermoplastic material having particles with a core and a shell, said shell being disposed on the surface of said core. And the core comprises aluminum.

Description

ELECTRONIC, ESPECIALLY OPTICAL OR OPTOELECTRONIC COMPONENT, AND METHOD FOR THE PRODUCTION THEREOF}

This patent application claims the priority of German Patent Application No. 10 2009 047 877.9 and German Patent Application No. 10 2009 055 765.2, the disclosures of which are hereby incorporated by reference.

The invention relates to an electronic, in particular an optical or optoelectronic device according to claim 1.

A widely known problem with optical or optoelectronic devices is that increasingly bright sources of radiation with higher operating temperatures and shorter wavelengths are used, thereby for example housing damage due to yellowing and chaking phenomena. It can happen. This can lead to damage to the reflector, for example, which significantly impairs important optical properties, such as the duration of operation of the device or luminous efficiency, and changes the luminescence characteristic curve.

An object of embodiments of the present invention is to provide an electronic device with improved yellowing characteristics.

The problem is solved by the electronic device according to claim 1. Further embodiments are the subject of further dependent claims.

Embodiments of the invention relate to electronics, in particular optical or optoelectronic devices, wherein the device has a component comprising a thermoplastic material, the thermoplastic material having particles comprising a core and a shell, The shell is arranged on the surface of the core and the core comprises aluminum. The part can also be made of thermoplastic material with particles. The core may comprise or consist of elemental aluminum.

Thermoplastic materials have good media resistance and sufficient temperature- and dimensional stability due to their thermodynamic properties. The thermoplastics also exhibit excellent crack resistance and cracks in cycle- and solder bath-stress of parts. Has strength. In addition, the low price enables economic mass production of the devices.

Aluminum particles have the following desirable properties: Aluminum particles are non-toxic and available at a low price on the market, and are non-corroding and medium resistant. The aluminum particles have a high thermal conductivity of about 220 W / mk. In the case where the aluminum particles have a shell (eg an oxide film on the surface), the aluminum particles have excellent electrical insulation properties at the same time due to the shell. Excellent metal reflectivity and at the same time high absorption in the wide wavelength range (UV to IR) make it possible to use the particles, in particular, for parts for optical or optoelectronic devices.

The present invention describes in this application with particular attention to optical or optoelectronic devices as representative of electronic devices. Implementations for optical or optoelectronic devices are correspondingly valid for electronic devices.

Parts comprising such thermoplastics having such particles with a core and a shell have, for example, improved adhesion to metal lead frames. This prevents moisture or other contaminants from penetrating into stress-prone component-lead frame-boundary surfaces. The increased barrier effect provided by adding the particles into the thermoplastic material reduces moisture absorption of the part and diffusion of toxic gases through the part.

Due to the improved thermal conductivity of the part, the loss of heat generated during operation of the device can also be more efficiently discharged, thereby reducing the aging of the part in the housing material. This can also raise the operating temperature of the device. In addition, the device may be processed at higher temperatures.

In further embodiments the shell is disposed directly above the surface of the core.

The core comprising aluminum is therefore directly surrounded by a shell. In one embodiment, the shell is firmly bonded to the surface of the core. For example, when the shell is produced or produced by a chemical reaction, in particular by a solid reaction such as oxide film formation, the shell is preferably bonded to the surface in a non-separable manner. Thus, preferably, the solid material constituting the shell is used.

In a further embodiment of the invention the shell comprises an oxide, nitride or oxynitride.

Shells made of these materials have excellent electrical insulation properties in combination with good thermal conductivity. In addition, the shells are non-toxic and have significantly higher corrosion and media resistance compared to metals. Preferably the shell likewise comprises aluminum, for example AlO ', AlN', AlO'Nxy.

In a further embodiment of the invention the shell has a thickness greater than 10 nm.

The shell of this thickness ensures sufficient electrical insulating properties and sufficient corrosion protection of the core of the particles.

In a further embodiment of the invention the shell has a thickness of less than 100 μm.

The thickness of the shell of less than 100 μm already has the aforementioned desirable properties. A thickness of less than 100 μm allows the particle size to be kept inherently small, which is particularly important for the optical properties of the part. The thickness of the shell is preferably in the range of 50 nm to 25 μm.

Particles with smooth surfaces are preferably used for the directional reflection of radiation, whereas particles with rough surfaces are preferably used for the diffuse reflection.

In a further embodiment of the invention the shell is electrically insulated.

This insulation of the core and the shell makes it possible to produce a core made of a conductive material and nevertheless use the particles in areas where the whole of the particles must be electrically insulated with respect to their surroundings. This situation therefore makes it possible to insert the particles into thermoplastic materials that can be used for parts to be inserted into optoelectronic devices. Thus, for example, a casting part may also be used as the part, which is disposed on the conductive parts of the optoelectronic device, which are not externally insulated, for example contact members. Since the particles have electrical insulation properties, preferably all thermoplastics have electrical insulation properties, thereby avoiding the risk of short circuits by the housing material made of thermoplastic material.

In a further embodiment of the invention the surface of the shell has at least partially coating.

As the coating, for example, a coating of grinding aid may be used. In one embodiment, a coating comprising a grinding aid is provided. As the grinding aid, for example, animal or vegetable lubricants and organic phosphonic acids or phosphonic acid esters can be used. As animal or vegetable lubricants, for example palmitic acid, stearic acid or oleic acid and salts of these substances with Zn, Ca, or Mg can be used.

The type and concentration of lubricants in this case can be chosen so that the particles are placed on the surface of the part and inserted less strongly within the part upon insertion into the thermoplastic and at the time of manufacture of the part to provide the desired reflective properties. In this case the concentration of lubricant may for example be in the range of 0.05 pbw to 3 pbw, based on the particles, in which case the range of 0.05 pbw to 1 pbw is preferred (pbw = parts by weight).

In another aspect the type and concentration of lubricant may be chosen to provide particularly good thermal conductivity by allowing the particles to be concentrated, particularly in the interior of the part.

If the particles are inserted into the part, in particular for the purpose of improving thermal conductivity, these particles thus preferably have a lower concentration of grinding additives inside the coating. In addition, these particles usually have a thin shell. Such thin shells result in cold shut defects of the particles at the contact points during manufacture.

In a further embodiment of the invention the particles have an average particle size of 10 nm to 50 μm measured as d ₅₀ -value.

The particles preferably have an average particle size of 10 nm to 20 μm measured as d ₅₀ -value. The size, shape and roughness of the particles can, for example, optimize the reflectivity. Likewise, the optical effects of the part can be affected by the size of the particles. Therefore, the metal optical means can be provided in the part using, for example, large particles and high concentration particles. In this case the average particle size can be defined by dynamic light scattering.

In a further embodiment of the invention, based on the thermoplastic, the concentration of the particles is in the range of 0.001 to 20% by weight, in which case the range of 0.001 to 5% by weight is preferred (weight-% = weight percent).

The concentration of particles in the thermoplastic is preferably between 0.001 and 1% by weight. The type and concentration of particles in the thermoplastic can control the reflectivity of the part comprising the thermoplastic. Thus, for example, metallic properties can be provided on the part surface.

In a further embodiment of the invention, the concentration of the particles is from 10 to 75% by weight, based on the thermoplastic.

In this case, for example, a device having a heat dissipation function may be used as the electronic, in particular the optical or optoelectronic device. Such devices preferably comprise flake-form multiphase particles. A high content of fillers can thereby be achieved.

In a further embodiment of the invention, the concentration of the particles is from 0.001 to 10% by weight, based on the thermoplastic.

In this case, as the optical or optoelectronic device, for example, a device having excellent reflective properties can be used. Such devices preferably comprise spherical particles having a smooth surface when the reflection should be directional. In contrast, when the reflection is diffuse, the device preferably comprises particles having a non-uniform and rough surface. In both cases, the particles are concentrated on the surface.

In a further embodiment of the invention the core has an aluminum content of at least 99 mol-%.

In an embodiment according to the invention the core has an aluminum content of 100 mol-%, which means that the core consists entirely of aluminum and in some cases traces of conventional impurities. Aluminum has been proven to be non-toxic and relatively inexpensive on the market. Aluminum also has a lower density than other metals, which results in very light particles.

In a further preferred embodiment of the invention the particles have a spherical, weakly-elliptic or similar form. For the weakly ellipsoidal form the radius ratio is ≦ 1.5.

In a further embodiment of the invention the particles have a flake form or a strongly ellipsoid form. In the case of a rigid ellipsoid, the radius ratio is> 1.5.

In an embodiment of the present invention, the particles have a fiber shape.

In the case where the particles have a flake form, fiber form or weakly ellipsoidal form, the particles preferably have an average particle size of 0.1 μm to 200 μm measured as d ₅₀ -value. In this case an average particle size of 1.0 μm to 50 μm is preferred and a range of 1.0 μm to 20 μm is particularly preferred.

Mixtures of various types of particles can be used as well as one type of particles to achieve the desired optical properties and the desired thermal conductivity. The same applies to the size of the particles. In the present invention, not only a single aspect of distribution may exist, that is to say that the particles may not only have a similar size, but also exist in various forms, that is, the particles have a distinct difference in their size.

By the shape of the particles the reflectivity can be controlled, for example, in the sense of directional or diffuse reflection.

Diffuse reflection can improve light complete mixing of radiation of different wavelengths, for example, on housing wall surfaces.

In the case where the particles have a flake form, a fiber form or a strong ellipsoidal form, the concentration of the particles is preferably 0.1 to 40% by weight, based on the thermoplastic material, in which case the range of 1.0 to 30% by weight is very preferred. Do.

In a further embodiment of the invention the core comprises or consists of an aluminum alloy.

The alloy may include, for example, Si and / or Mg. Preferably the alloy comprises Si. Such alloying components stabilize the core of the particles. For weight percentages based on the amount of aluminum used, the concentration of the alloying component is preferably in the range of 10 ppm to 0.9 weight-%.

In a further embodiment of the present invention the thermoplastic further comprises one or more additive materials selected from the following materials: glass fibers, glass tissue, glass powder, TiO 2, CaCO 3, BaSO Ba, Al 2 O 3, SiO 2, ZrO 2, such as White pigments, light-converging materials, dyes, additives such as surfactant-active agents, stabilizers, inorganic and metal nanoparticles such as ZnO, ZrO2, Au, Ag, Ti, organic phosphor flame retardants.

In a further embodiment of the present invention, the thermoplastic material may be polyarylether, polyphenylether, polysulfone, polyaryleneethersulfone, polyaryletherketone, polyetherimide, polycarbonate, polyamide, polytetrafluoroethylene Plastics selected from fluorine-containing polymers such as, tetrafluoroethylene-perfluoropropylene copolymers, polyvinylidene fluoride, polyvinyl fluoride, LCP and mixtures of various thermoplastics are used. In this case, polyphthalamide in the polyamide is preferred.

In this case the polyamide may further be mixed with glass fibers, glass tissues, carbon black or white dyes.

In a further embodiment of the invention a housing is used as part. Such a housing may for example be formed as a reflector. The housing may for example comprise a radiation source therein.

Electronics, in particular optical or optoelectronic devices, can be used, for example, in one of the following areas: automotive area, cooling media with optical functions, optical structure housing and frame material in photovoltaic installations, medical- or sanitary domain. In this case the device may be for example an automobile headlamp, an optical module, a signal fixture or a large area optical design-member or may be a component part of the areas. The use of such devices is of particular interest due to the low weight and heat releasing properties of thermoplastics with particles.

In addition, electronics, in particular optical or optoelectronic devices, can be used in modules and systems with elevated reliability and can be applied within stringent operating conditions. Or it may be used in new applications with an extended functional area, for example as a housing for surface-mounted device (SMD) -enabled LEDs.

The invention also relates to the use of the aforementioned thermoplastics for the production of components for electronics, in particular for optical or optoelectronic devices.

The above-described thermoplastics with particles can be used, for example, in housings and / or reflectors, optical modules, signal fixtures and large area optical design-members in a headlamp. In this case it may be advantageous for the effect of dissipating the small weight and heat of the thermoplastic or parts comprising the thermoplastic. For the same reason, the above described thermoplastics with particles are suitable as frame material in photovoltaic applications.

The above described thermoplastics with particles can be used as synthetic materials processed into thermoplastics. In this case design flexibility is obtained, and as a result such composite material can be used, for example, in inexpensive heat dissipation channels in electronic devices, modules and systems.

In addition to the device itself, the invention also relates to a method for manufacturing components for electronics, in particular for optical or optoelectronic devices.

In a variant of the method according to the invention for producing a component for an electronic, in particular an optical or optoelectronic device, the method comprises the following method steps: providing thermoplastic material as method step A), method step B) Inserting particles comprising or consisting of a core and a shell, wherein the shell is disposed on the surface of the core, the core comprises aluminum, and forming a part as method step C). step.

The advantages mentioned in connection with the device in this case are also valid for the method in a similar manner.

In a further variant of the method according to the invention the particles in method step B) are produced in a preceding method comprising the following steps: melting aluminum as method step a), method step as method step b) Atomize the melt made from a), as a result of which cores are formed.

In a further variant according to the invention this preceding method further has the following steps: grinding of the core made from the method step (b) as method step c).

In a further variant according to the invention this preceding method further has the following steps: conditioning the core as method step d), resulting in the formation of a shell on the surface of the core. In this case the method step d) can be carried out before or after the method step c).

In this case the shell can also be formed between the core and the coating disposed on the core. In this case the coating can be partially removed by conditioning.

In the following paragraphs one embodiment is described in more detail. For example, high purity aluminum having a content of less than 99 mol-% is melted at a temperature of about 700 ° C. in process step a). In the subsequent method step b) Molten aluminum is sprayed by air or an inert gas (nitrogen, Ar, He) at high pressure. Spraying systems and spraying parameters affect the size and shape of the core. By this means, already indirectly, for example, the thickness of a later shell can be affected. The cores are ground in the subsequent method step c). As the grinding process, for example, wet milling in hydrocarbons, test benzine, petroleum ether or toluol can be used. Such a process may be carried out at a temperature of, for example, 70 ° C. or less. The grinding can be carried out using, for example, spherical grinding media of defined size and amount. In the grinding step, grinding aids can be added, for example waxes, oleic acid, stearic acid or palmitic acid. The particle shape in this case depends very much on the grinding energy used and the hardness of the grinding media.

In a further variant according to the invention the grinding aid with the organic solvent is completely or partially separated by washing.

In a further variant according to the invention the particle size and particle distribution are optimized by the filtration process.

Conditioning of the core in process step d) can take place at a temperature of 400 ° C., for example in an oven. The conditioning can be for example for a time of 1 to 12 hours. In the present invention, for example, air, oxygen, nitrogen or argon may be used as the atmosphere. Further surface modifications, such as for example passivations, can also be carried out in plasma (oxygen, air, argon and mixtures thereof). In this case the plasma power and the duration of the plasma treatment can be adjusted according to the desired target definition. The particles obtained by this process are stable to moisture and stable to hydrolysis even over the entire pH-value-range.

In a further variant of the method according to the invention the particles before method step B) and after method step d) are dried in method step e). The drying process can take place, for example, for a time of 1 to 12 hours at a temperature of 120 ° C. In this case, a vacuum (13 mbar or less) may also be applied at the same time.

In a further variant of the method according to the invention the processing of the thermoplastic comprises the following process steps: conditioning, drying, homogenizing and shaping the raw material. Each step can be done independently of one another in an atmosphere comprising air or an inert gas. In this case the inert gas atmosphere may comprise nitrogen, argon or helium, for example in the case of not wishing to form a shell comprising AlO 'in this process step. It makes sense.

The method may further comprise a wet chemical- or dry chemical-physical process.

The thermoplastic materials described above can be used, for example, for cooling in optical or optoelectronic devices. The thermoplastic can therefore be used for example for SMD-devices which can be applied in the automotive industry, for example.

- 이온들을 배출할 수 있는 알루미늄-원들(aluminium source)로서 작용할 수 있다. In addition, the thermoplastic materials described above may be used, for example, to minimize corrosion in lead frames. In this case, for example, silvered lead frames may be used. Such lead frames can be cast, for example, by silicon or silicon hybrid. Particularly well suited for this purpose are thermoplastics comprising particles having a shell of less than 5 μm, preferably of less than 1 μm. These thermoplastics Al³

Act as an aluminum source capable of releasing ions.

In the following, modifications of the present invention are described in more detail with reference to the drawings and embodiments.

1A and 1B show schematic cross-sectional views of particle embodiments, respectively.
2A and 2B show schematic cross-sectional views of optoelectronic device embodiments, respectively.

1a shows a schematic cross section of a particle 1. These particles consist of a core 2 and a shell 3 arranged just above the surface of the core 2.

1b shows a schematic cross section of a further embodiment of the particle 1. Such particles further comprise a coating 4 disposed directly on the surface of the shell 3 as compared to the particles shown in FIG. 1A.

2A shows a schematic cross section of an embodiment of an optoelectronic device. This device comprises a part 6 made from a thermoplastic 5. The thermoplastic material 5 comprises particles 1. In this embodiment the component 6 is formed as a reflector. The radiation source 7 is arranged inside the reflector well. As the radiation source 7, for example, an inorganic LED or an organic LED (OLED) can be used. The radiation source 7 is cast by a casting 8 which forms a lens 9 at the radiation emitting surface. The radiation emitted from the radiation source 7 can be reflected by the reflector, thereby increasing the light efficiency of the optoelectronic device. Heat generated during operation of the radiation source can be discharged to the surroundings by the component 6. In this case the thermal conductivity is markedly increased by the particles 1 inserted in the thermoplastic material 5. Such an embodiment is, for example, well suited for component heat dissipation. The particles preferably have a large surface as in the case of flake form.

LEDs include semiconductors that form diodes. LEDs are often so-called III / V-semiconductors, ie composed of elements of groups 3. and 5. of the periodic table. The LED also includes, for example, an anode located on the top surface of the LED and a cathode that can be correspondingly disposed on the bottom surface. The anode can be conductively connected to the conductor frame through which the LED can be placed via a bonding-wire. When a voltage is applied in the forward direction, the electrodes move from the p-n-junction to the recombination layer. On the n-doped side the electrodes fill the conduction band to move to the more efficient p-doped valence band in terms of energy as it exceeds the interface. The electrodes then recombine with existing holes there.

OLEDs have a layer stack comprising an anode and a cathode. Electrodes which move in the direction of holes or different electrodes through the application of voltage from the anode and cathode are sent out. In this case the charge carriers migrate before they collide with each other in the light emitting layer, for example through hole- or electrode-transporting layers. Electrons in this layer form excitons by holes. The excitons can excite luminescent materials present in the emissive layer to emit radiation. The OLED may comprise an organic functional layer, and as the organic functional layer, for example, a layer that emits light, blocks charge carriers, or transports charge carriers may be used, or a combination thereof may be used. .

2B shows a schematic cross section of a further embodiment of the optoelectronic device. The optoelectronic device likewise comprises a component 6 made from a thermoplastic 5 as in the embodiment shown in FIG. 2A. The thermoplastic material 5 comprises particles 1. Even in this case, the component 6 is formed as a reflector. The radiation source 7 is arranged inside the reflector well. As the radiation source 7, likewise an inorganic LED or an organic LED (OLED) can likewise be used. The radiation source 7 is cast by a casting 8 which forms a lens 9 at the radiation emitting surface. In contrast to the embodiment shown in FIG. 2A, in this embodiment the particles 1 are arranged on the surface of the part 6. The surface thus has a very high reflectance. If the reflector must be directional, the thermoplastic material preferably comprises spherical particles having a smooth surface. On the contrary, if the reflector must be diffuse, the thermoplastic material preferably comprises particles having a non-uniform rough surface.

The present invention is not limited to the above embodiments due to the detailed description with reference to the embodiments. Rather, the invention includes each new feature and each combination of features, in particular each feature combination being included in the claims even if the feature or the combination itself is not expressly described in the claims or the embodiments. To be considered.

Claims (15)

As electronics, in particular optical or optoelectronic devices, comprising the component 6,
The part comprises a thermoplastic material 5 having particles 1 with a core 2 and a shell 3, the shell 3 being arranged on the surface of the core 2, the The core 2 comprises aluminum,
Electronics, in particular optical or optoelectronic devices. The method of claim 1,
The shell 3 is disposed directly above the surface of the core 2,
Electronics, in particular optical or optoelectronic devices. 3. The method according to claim 1 or 2,
The shell 3 comprises an oxide, nitride or oxynitride,
Electronics, in particular optical or optoelectronic devices. 4. The method according to any one of claims 1 to 3,
The shell 3 has a thickness greater than 10 nm,
Electronics, in particular optical or optoelectronic devices. The method according to any one of claims 1 to 4,
The shell 3 has a thickness of less than 100 μm,
Electronics, in particular optical or optoelectronic devices. The method according to any one of claims 1 to 5,
The shell 3 electrically insulates the core 2,
Electronics, in particular optical or optoelectronic devices. 7. The method according to any one of claims 1 to 6,
The surface of the shell 3 has a coating 4,
Electronics, in particular optical or optoelectronic devices. 8. The method according to any one of claims 1 to 7,
The particles 1 have an average particle size of 10 nm to 50 μm, measured by d ₅₀ -value,
Electronics, in particular optical or optoelectronic devices. 9. The method according to any one of claims 1 to 8,
Based on the thermoplastic, the concentration of the particles 1 is between 0.001 and 5% by weight,
Electronics, in particular optical or optoelectronic devices. 10. The method according to any one of claims 1 to 9,
The core 2 has an aluminum content of at least 99 mol-%,
Electronics, in particular optical or optoelectronic devices. 11. The method according to any one of claims 1 to 10,
The core 2 comprises an aluminum-alloy,
Electronics, in particular optical or optoelectronic devices. 12. The method according to any one of claims 1 to 11,
The part 6 is a housing,
Electronics, in particular optical or optoelectronic devices. A) preparing a thermoplastic material (5),
B) inserting particles (1) comprising a core (2) and a shell (3), wherein the shell (3) is arranged on the surface of the core (2), the core (2) being Contains aluminum
C) forming a part 6,
A method for manufacturing a component (6) for electronic, in particular optical or optoelectronic devices. The method of claim 13,
The particles 1 in method step B)
a) melting aluminum,
b) spraying the melt made from method step a), as a result of which a core 2 is formed,
c) grinding the core 2 made from method step b),
d) conditioning in the core 2 made from the method step c), as a result of which a shell 3 is formed on the surface of the core 2,
Method for manufacturing components for electronics, in particular optical or optoelectronic devices. The method of claim 14,
The particles 1 before method step b) and after method step d) are dried in method step (e),
Method for manufacturing components for electronics, in particular optical or optoelectronic devices.

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